A-League boss admits a small number of fans are problematic

The head of soccer's A-League has admitted there is a small group of fans who persistently cause problems after supporters lit flares and wore balaclavas outside yesterday's grand final between Sydney FC and Melbourne Victory.

While authorities have praised the majority of soccer fans who attended the game at AAMI Park in Melbourne, the behaviour of some supporter groups outside the event has been labelled "disappointing".

Police said a number of supporters acted aggressively towards rival supporters at a pub, prompting officers to use capsicum spray to break up the crowd.

Anyone who lets a flare off inside a stadium is issued with a five-year ban. (9NEWS) (9NEWS)

A 20-year-old Miners Rest man has been issued with a penalty notice, while a 17-year-old Frankston youth has been charged with behaving in a riotous manner.

Several flares were lit outside the park, and photos have emerged of some fans wearing balaclavas or covering their faces as they marched to the football ground.

Police say this portrays "an image more aligned to that of criminals hiding their identities than to genuine football fans".

Victoria Police said football fans who cover their faces portray an image more aligned to criminals. (9NEWS) (9NEWS)

Head of the A-League Damien De Bohun says police have told him personally how pleased they are with how fans behaved at the match.